Davis attended the Stowe School before obtaining a medical degree at the School of Clinical Medicine of the University of Cambridge. He completed his residency at Middlesex Hospital, and returned to Cambridge to work at the university hospital. Davis was named reader of clinical psychology in 1950, and began teaching medical psychology in 1958, when he was appointed as Director of the Medical Psychology Laboratory. He left for Bristol University in 1962 and taught there until 1979.
